International Patent Application Publication Number WO 2004/046115 provides certain 4-oxoquinolone compounds that are useful as HIV integrase inhibitors. The compounds are reported to be useful as anti-HIV agents.
International Patent Application Publication Number WO 2005/113508 provides certain specific crystalline forms of one of these 4-oxoquinolone compounds (i.e. 6-(3-chloro-2-fluorobenzyl)-1-[(S)-1-hydroxymethyl-2-methylpropyl]-7-methoxy-4-oxo-1,4-dihydroquinolone-3-carboxylic acid). The specific crystalline forms are reported to have superior physical and chemical stability compared to other physical forms of the compound.
International Patent Application WO2009/036161 and International Patent Application WO2008/033836 describe methods for preparing the 4-oxoquinolone compounds reported in WO 2004/046115 and WO 2005/113508.
There is currently a need for improved methods for preparing the 4-oxoquinolone compounds reported in International Patent Application Publication Number WO 2004/046115 and in International Patent Application Publication Number WO 2005/113508. In particular, there is a need for new synthetic methods that are simpler or less expensive to carry out, or that require fewer synthetic steps, or that provide an increased yield, or that eliminate the use of toxic or costly reagents or wherein the starting materials are easier to use or purify.